Gently ‘bounce’ long arm allen key.
Repeat with gentle tapping from rubber mallet.
Repeat with larger lump hammer plus odd choice word.
Pause for thought.
Apply penetrating oil, make a cup of tea, take a calm breath and hit with hammer again.
Remove crank and place in vice, increasing strength of hammer blows and volume of language used.
Come to the realisation you’re braying it in the wrong direction.
Have a man cry.
Turn round crank, apply short sharp blow with hammer and loosen pedal, taking as much skin off your knuckles as possible.
Have another cup of tea (leaving grease/bloodstains at points most likely to annoy missus).
Marvel in your own glory as a home mechanic.